Centrifugal bucket



uy l2 394% R. J. BIRKENHAUER CENTRIFUGAL BUCKET Filed NOV. 23, 1945 INVEN TOR.

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riphery of the cake.

Patented July 12, 1949 2,415,735 cENrmFUGAL BUCKET Robert J.Birkenhauer, Richmond, Va., asslgnor to E. I. du Pont de Nemours 8aCompany, Wilmington, Del., a corporation o! Delaware i ApplicationNovember 23, 1945, Serial No. 630,498

1 claims. l

This invention relates to centrifugal buckets. More particularly. itrelates to centrifugal spinning buckets employed in the bucket processof producing synthetic yarn.

One of the common methods of preparing viscose rayon yarn,l i. e.regenerated cellulose yarn produced from viscose, is known as the bucketprocess. According to such process. a solution of viscose is extrudedthrough a 'suitable nozzle or spinneret into a coagulating andregenerating bath from which the filaments of regenerated cellulose arewithdrawn by a feed wheel and fed by an appropriate traversing guideinto the interior of a bucket rotating at high speed. The centrifugalforce created by the rotation of the bucket draws the yarn from thetraversing guide and throws it againstthe wall of the bucket or againstthe layers of yarn previously laid down. The traversing guide isreciprocated axially of the bucket between the top and bottom thereof sothat the yarn, as it is laid against the wall of the bucket, forms ahelix.

After a cake of'suitable size is formed, it is doffed and the yarn isprocessed either in cake form as spun or after re-winding into skeins.The processing of the yarn involves treatment with various liquids inorder to remove the acidv acid and soluble salts contained therein andto desulfur, bleach, dye o r otherwise treat to impart desirablecharacteristics to the finished product. The finished yarn, irrespectiveof the form in which it is processed, is wound into the final textilepackages, such as cones, in which form they are supplied to the textileindustry.

The inner peripheral wall'of one of the most commonly used types ofbucket tapers about 3 upwardly from the bottom to the top of the bucket.During the formation of the cake, the cake undergoes endwise shrinkageand pulls away from both the bottom of the bucket and the bucket lid.Consequently, during the formation of the cake, the yarn will be thrownby the centrifugal force over the top and bottom of the cake to formloose threads on the outer pe- Such loose threads are known in the artas ears, and interfere with the unwinding of the yarn from the cake. Insome instances, particularly when the yarn is formed into the finaltextile package from processed cakes, the ears cause breaks and plucks.Frequently, the change in tension on the yarn, during the formation ofthe final textile package, caused by the ears results in yarn whichproduces shiners in fabric made therefrom.

The results obtained because of the ears can be avoided if the ears arestripped from the cake. This requires unwinding of the yarn until theears are removed and discarding of such unwound yarn as waste. y

An object of this invention is to provide a new and improved centrifugalbucket.

`Another object of this invention is to provide a spinning bucket whichwill produce a yarn cake of improved-formation.

A further object of this invention is to provide a centrifugal bucket ofa construction wherein the vertical component of the centrifugal forceproduced by the rotation of the bucketI opposes the tendency of the caketo shrink endwise.

An additional object of this invention is to provide a centrifugalbucket wherein the vertical component of the centrifugal force producedduring the rotation of the bucket wil1 be both upward from the center ofthe bucket.

Other and additionalobjects will become ap v parent hereinafter.

The above objects are accomplished, in general, by a new construction ofa centrifugal bucket in which the inner wall thereof on which the yarnis laid is tapered in opposite .directions to a point substantiallymidway between the top and bottom of the bucket, whereby, during the.

formation of the yarn cake, the vertical cornponent of the centrifugalforce from such central point is in opposite directions (upward anddownward) and opposes the shrinkage forces in the yarn of the caketending to shrink the cake endwise, i. e. pull away from the lid andbottom of the bucket, and thereby prevent the formation of ears. i ,l

The present invention will be more clearly Vunlderstood by reference tothe detailed description when taken in connection with the accompany--`ing drawings, wherein:

Figure 1` is a vertical section of Aone ment of a bucket of the instantinventionQincluding also a portion of the cooperating traversing guide;y.

Figure 2 is another embodiment of the bucket constituting thisinvention; and

Figure E3 is still another embodiment of this invention.

Referringl now to the drawings wherein like reference numerals designatelike parts, and particularly to Figure 1, the reference numeral I0designates a bucket in which the side wall I2 is formed integrally withthe bottom I4 and isV normally open at the top. The bottom I4 isprovided with an integral hub I6 whereby the bucket may be positioned ona rotating spindleof a spinning machine. 'Ihe bucket is provided with alid I8 which is seated on an annular shoulder and is held in position bya spring clip 20. The lid I8 is yprovided with a circular hole 22 in thecenter thereof, through which a traversing guide 24 passes. Thetraversing guide 24 is reciprocated by a traversing bar (not shown) -sothat it will travel axially of the bucketifrom the top to the bottomthereof whereby the yarn will be drawn by the centrifugal force from thetraversing guide and laid down on the inner peripheral wall of the wallof the bucket is tapered from the central point 26 in both directions toform two oppositely disposed frusto-conical surfaces 28 and 30. 1n theform shown in Figure 1, the frusta-conical surface 28 has a taper of 1in the downward direction, and the frusto-conical portion 30 has a taperof 1 in the upward direction. Adjacent the bottom, the bucket isprovided with drain holes 32 to permit draining of any liquids carriedby or supplied to the yarn.

The invention is not restricted to the previously described embodimentwherein the double taper of the inner peripheral wall of the bucket isformed of two frusto-conical surfaces. The inner peripheral wall of thebucket, as shown in Figure 2, can comprise a smooth inwardly curvedsurface 40, or two smooth outwardly curved surfaces 42 and 44, as shownin Figure 3. The peripheral wall 40 is tangent to a vertical line at apoint midway between the top and bottom of the bucket. The bottom of thecurved section 42 and the top of the curved section M unite at a pointwhich is midway between the top and bottom of theI bucket.

Though, as previously described, the taper of the wall in oppositedirections from the center thereof is 1, the invention is not restrictedthereto. The taper of the wall in opposite directions from the centerthereof can be as much as 3 or more, depending on the amount ofshrinkage that takes place in the inside of the cake, or as little as1,11%". In order that the vertical component of the centrifugal force bethe same, 'it is prefe'rred that the taper in the opposite direction beof the same angular magnitude.

The bucket can be used in the bucket spinning process for themanufacture of synthetic yarn from viscose, cuprammonium cellulose,cellulose acetate, etc. It can also be used for theprocessing of yarncakes produced therein or in similar buckets.

In operation, the bucket is positioned on a spindle which is rotated ata high speed. The yarn, after leaving the feed wheel which withdraws thefilaments from the bath in which a viscose solution is extruded, passesto the reciprocating traversing guide from which it is drawn by thecentrifugal force and laid down'in the form of a helix on the inner wall.of the bucket. This operation is continued until an annular cake ofdesired size is obtained. When 150denier60 filament viscose rayon hightenacity yarn spun by the hot dip process was collected in a bucket cfthe construction' such as shown in Figure 1, with the traverse being 53strokes per minute, there was produced after 5 hours an annular cakefree of ears and of acceptable cake formation. When a standard 3 taperbucket was used under identical conditions, there was produced a cakehaving very bad ears.

It is to benoted that the cakes can be doed from buckets of the typeherein described because, after a, bucket has been stopped, the bottomof the cake actually has a diameter smaller than the restricted regionat the center of the bucket.

The buckets are made of materials which are corrosion-resistant andnormally inert with respect to the iiuids contained by the yarn after itleaves the spinning bath and also to the uids employed when the cake isprocessed in the bucket. .In general, satisfactory results are obtainedwhen the bucket is made of materials such as rubber,resinous-condensation products, and the like.

The invention provides a centrifugal bucket 4 which produces a bucketcake of acceptable formation and substantially free of ears whereby theyarn can be readily unwound either into skeins or final textile packageswithout waste, plucks or production of yarns which produce shiners infabrics made therefrom.

Since it is obvious that many changes and modifications can be made inthe above-described details without departing from the nature and spiritof the invention, it is to be understood that the invention is not to belimited thereto except as set forth in the appended claims.

I claim:

1. A centrifugal bucket having its inner wall tapered in oppositedirections with the smaller diameter of each tapered portion uniting atsubstantially midway between the top and bottom of said bucket.

2. A centrifugal bucket having its inner wall tapered from about 1/ toabout 3 in opposite directions with the smaller diameter of each taperedportion uniting at substantially midway between the top and bottom ofsaid bucket.

3. A centrifugal bucket having its inner wall tapered about 1 inopposite directions with the smaller diameter of each tapered portionuniting at substantially midway between the top and bottom of saidbucket.

4. A centrifugal bucket having its inner wall tapered in voppositedirections with the smaller diameter of each tapered portion uniting atsubstantially midway between the top and bottom of said bucket, the saidinner wall comprising two frusto-conical surfaces uniting at theirsmaller diameters substantially midway between the top and the bottom ofsaid bucket.

5. A centrifugal bucket having its inner wall tapered in oppositedirections with the smaller diameter of each tapered portion uniting atsubstantially midway between the top and the bottom of said bucket, thesaid inner wall comprising a smooth inwardly curved surface which istangent to a vertical line at a point substantially midway between thetop and bottom of said bucket.

6. A centrifugal bucket having its inner wall tapered in oppositedirections with the smaller diameter of each tapered portion uniting atsubstantially midway between the top and bottom of said bucket, the saidinner wall comprising two outwardly curved surfaces, the top of onesurface and the bottom of the other surface uniting substantially midwaybetween the top and bottom of said bucket.

7. A centrifugal bucket having inside diameters shorter toward thecenter than toward the bottom and toward the top and the inner surfacesof its side walls tapered in opposite directions with the smallestdiameter of each tapered portion uniting at substantially midway betweenthe top and bottom of said bucket.

ROBERT J. BIRKENHAUER.

REFERENCES CITED The following referenlces are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,663,555 Jessen Mar. 27, 1928FOREIGN PATENTS Number Country Date 483,089 Germany Sept. 25, 1929Certificate of Correction July 12, 1949 Patent No. 2,475,735

ROBERT J. BRKENHAUER It is hereby eertiel that errors appear in theprinted specieation of the above numbered patent requmng correction asfollows: Column l, line 27, strike out the Word acid from 1 insert anddownwar uld be read with these corrections therein that and that thesaid Letters Patent sho f the case 1n the Patent OHee.

the same may conform to the record o y of January, A. D. 1950.

Signed and sealed this 31st da column 2, line 12, before THOMAS F.MURPY,

Assistant Uommz'ssz'oner of Patents.`

